The Australian National University is still counting the cost of Sunday's storm, listing damage to rare books,delays to the Union Court redevelopment and the writing off of up to 11 excavators as among major issues caused by the deluge.

About 22,000 students and 4500 staff were asked to stay away from the university on Monday as it closed for the first time in more than a decade.

The weekend's downpour hit ANU's inner north campus hard. The Sullivans Creek weather station recorded 164.4mm of rain in the 48 hours from 10am Saturday, most of which fell within a couple of hours, according to the Bureau of Meterology.

Insurance assessors will visit the university on Tuesday but already ANU officials have warned the clean-up could take up to 12 months in at least one building.

Advertisement

Sullivans Creek was still flowing strongly on Monday.Credit:Sherryn Groch

ANU chief operating officer Chris Grange said the lower level of the AD Hope Building - home to the School of Anthropology and Archaeology - would have to be stripped and renovated after being flooded by four inches of water.

"We haven't suffered much damage to the materials, to the papers, to the laboratories to that school, but it's a sodden mess," Mr Grange said.

"We're currently working on how we can renovate that and how we can find alternative accommodation for a group of staff, postgraduate students, visitors and for their laboratory activities."

The lower level of Chifley Library, the biggest and busiest among the ANU's five libraries, suffered half a metre of water.

Books in the library were badly damaged.Credit:Sherryn Groch

The flooding wiped out Chifley's electrical distribution boards, air conditioning and ventilation systems and IT infrastructure, as well as causing untold damage to microfilm collections, books, serials and journal articles relating to history, philosophy and politics.

"It will possibly be very difficult to replace some of those, but it's too early to pass an overall assessment," Mr Grange said of the books.

ANU management spoke with the site manager of the Union Court redevelopment project, Lendlease, on Sunday and Monday about extensive flooding of the construction site.

Workers made the site safe on Monday and will return Tuesday to drain the area, which will eventually become student services hub Kambri. Some equipment was damaged.

Mr Grange said: "Eleven excavators went underwater [on Sunday] and Lendlease have concerns for all of them, so most of them may well be written off."

The university was investigating reports that materials related to the project had swept into Sullivans Creek.

Site manager Lendlease pointed to ANU media when asked for comment.

Toad Hall and the Tjabal Centre also received flood damage.

The university will reopen on Tuesday. Kambri construction work will restart and Chifley Library likely reopen by the end of the week.

A "very small" number of classes will be relocated.

Mr Grange said he believed the ANU was well-prepared for extreme weather events.

"[Sullivans Creek] broke its banks in a number of different places and really that's a product of the water volumes from upstream," he said.

Loading

"I think it would be very difficult for us to do anything about that."

The last campus-wide closure was also caused by the weather, when a supercell hailstorm tripped fire alarms, collapsed ceilings and covered the campus in a heavy coating of huge hail stones on February 28, 2007.